Starter replaced, next day the O2 sensor goes out?

2003 Pontiac Vibe:

7/2011 - Check Engine Light came on -mechanic cleaned mass air sensor and did tune up. Cleared code.

11/14/11 - Car won't start, then does start. Mechanic replaces starter.

11/15/11 Car makes whirring noise when starting. Gets no power. Mechanic replaces O2 sensor. Cleans mass air sensor again.

We find it odd that the day after the starter replacement was done, the O2 sensor goes out? There had been no previous issues with engine except the one mentioned in 7/2011. Otherwise, the car had been running fine before the starter went out and was repaired.

combined costs were $525